Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.
Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.
A jealous Leonard reacts to Penny's new guy by rebounding with Leslie.
Sheldon creates a monster when he introduces Penny to online gaming.
Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.
Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.
Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.
Leonard asks Penny for advice when his new relationship starts moving too fast.
Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.
Sheldon creates a scientific procedure for making friends.
Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.
A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.
Penny's home business turns into a complete nightmare when Sheldon takes over.
A fellow comic book enthusiast's hitting on Penny leads to Leonard and Howard going to a bar's Ladies' Night.
Leonard and Koothrappali escort a heartbroken Wolowitz to Las Vegas, and Sheldon becomes locked out of his apartment and must stay with Penny.
Howard and Raj visit a Goth nightclub to pick up women while Sheldon attempts to build a better Penny using chocolate-based behavior modification.
Raj must find a new job or be sent back to India, but Sheldon has a solution, which leaves Leonard and Penny dealing with Howard as a third wheel.
After overhearing that Wil Wheaton is entering a trading-card competition, Sheldon decides to enter it himself. Meanwhile, Penny sets up one of her friends on a date with Wolowitz.
Sheldon becomes Leonard's teacher in order to understand football, while an incident with flying a kite threatens Howard and Raj's friendship.
After he's humiliated on National Public Radio, Sheldon vows to destroy Kripke, while Wolowitz tries not to destroy his new relationship with Bernadette.
Penny gets help from Sheldon in order to understand what Leonard's work is, while Wolowitz develops a jealousy when Leonard starts hanging out with his new girlfriend.
Leonard is aghast to find out a secret of Penny's: she believes in psychics. Meanwhile, Sheldon tries to assist Koothrappali in picking up a girl at a university mixer.
Sheldon winds up in traffic court when he gets a ticket because of Penny.
Sheldon's friends come to his aid when his fear of public speaking stands between him and a coveted award.
While Penny worries that dating Leonard has ruined her for normal guys, Wolowitz and Koothrappali search for Sheldon's perfect match online.
Penny tags along on Sheldon's first ever date; Wolowitz finds a new use for a robotic arm.
Realizing he will not live long enough to download his consciousness into a robot body, Sheldon tries to extend his life span.
An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.
Leonard keeps an affair a secret from Sheldon, Howard and Raj.
Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.
Leonard's idea for a smartphone app derails his friendship with Sheldon.